Add improved docs

Author: wooorm

readme.md

@@ -8,39 +8,98 @@
 [![Backers][backers-badge]][collective]
 [![Chat][chat-badge]][chat]
 
-Extension for [`mdast-util-from-markdown`][from-markdown] and/or
-[`mdast-util-to-markdown`][to-markdown] to support GitHub flavored markdown
-autolink literals in **[mdast][]**.
-When parsing (`from-markdown`), must be combined with
-[`micromark-extension-gfm-autolink-literal`][extension].
+[mdast][] extensions to parse and serialize [GFM][] autolinks.
+
+## Contents
+
+*   [What is this?](#what-is-this)
+*   [When to use this](#when-to-use-this)
+*   [Install](#install)
+*   [Use](#use)
+*   [API](#api)
+    *   [`gfmAutolinkLiteralFromMarkdown`](#gfmautolinkliteralfrommarkdown)
+    *   [`gfmAutolinkLiteralToMarkdown`](#gfmautolinkliteraltomarkdown)
+*   [Syntax tree](#syntax-tree)
+*   [Types](#types)
+*   [Compatibility](#compatibility)
+*   [Related](#related)
+*   [Contribute](#contribute)
+*   [License](#license)
+
+## What is this?
+
+This package contains extensions that add support for the autolink syntax
+enabled by GFM to [`mdast-util-from-markdown`][mdast-util-from-markdown] and
+[`mdast-util-to-markdown`][mdast-util-to-markdown].
+
+GitHub employs different algorithms to autolink: one at parse time and one at
+transform time (similar to how @mentions are done at transform time).
+This difference can be observed because character references and escapes are
+handled differently.
+But also because issues/PRs/comments omit (perhaps by accident?) the second
+algorithm for `www.`, `http://`, and `https://` links (but not for email links).
+
+As the corresponding micromark extension
+[`micromark-extension-gfm-autolink-literal`][extension] is a syntax extension,
+it can only perform the first algorithm.
+The tree extension `gfmAutolinkLiteralFromMarkdown` from this package can
+perform the second algorithm, and as they are combined, both are done.
 
 ## When to use this
 
-Use [`mdast-util-gfm`][mdast-util-gfm] if you want all of GFM.
-Use this otherwise.
+These tools are all rather low-level.
+In most cases, you’d want to use [`remark-gfm`][remark-gfm] with remark instead.
 
-## Install
+When you are working with syntax trees and want all of GFM, use
+[`mdast-util-gfm`][mdast-util-gfm] instead.
 
-This package is [ESM only](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c):
-Node 12+ is needed to use it and it must be `import`ed instead of `require`d.
+When working with `mdast-util-from-markdown`, you must combine this package with
+[`micromark-extension-gfm-autolink-literal`][extension].
 
-[npm][]:
+This utility does not handle how markdown is turned to HTML.
+That’s done by [`mdast-util-to-hast`][mdast-util-to-hast].
+
+## Install
+
+This package is [ESM only][esm].
+In Node.js (version 12.20+, 14.14+, or 16.0+), install with [npm][]:
 
 ```sh
 npm install mdast-util-gfm-autolink-literal
 ```
 
+In Deno with [`esm.sh`][esmsh]:
+
+```js
+import {gfmAutolinkLiteralFromMarkdown, gfmAutolinkLiteralToMarkdown} from 'https://esm.sh/mdast-util-gfm-autolink-literal@1'
+```
+
+In browsers with [`esm.sh`][esmsh]:
+
+```html
+<script type="module">
+  import {gfmAutolinkLiteralFromMarkdown, gfmAutolinkLiteralToMarkdown} from 'https://esm.sh/mdast-util-gfm-autolink-literal@1?bundle'
+</script>
+```
+
 ## Use
 
-Say our module, `example.js`, looks as follows:
+Say our document `example.md` contains:
+
+```markdown
+www.example.com, https://example.com, and [email protected].
+```
+
+…and our module `example.js` looks as follows:
 
 ```js
+import fs from 'node:fs/promises'
 import {fromMarkdown} from 'mdast-util-from-markdown'
 import {toMarkdown} from 'mdast-util-to-markdown'
 import {gfmAutolinkLiteral} from 'micromark-extension-gfm-autolink-literal'
 import {gfmAutolinkLiteralFromMarkdown, gfmAutolinkLiteralToMarkdown} from 'mdast-util-gfm-autolink-literal'
 
-const doc = 'www.example.com, https://example.com, and contact@example.com.'
+const doc = await fs.readFile('example.md')
 
 const tree = fromMarkdown(doc, {
   extensions: [gfmAutolinkLiteral],
@@ -54,7 +113,7 @@ const out = toMarkdown(tree, {extensions: [gfmAutolinkLiteralToMarkdown]})
 console.log(out)
 ```
 
-Now, running `node example` yields:
+…now running `node example.js` yields (positional info removed for brevity):
 
 ```js
 {
@@ -96,34 +155,54 @@ Now, running `node example` yields:
 
 ## API
 
+This package exports the identifiers `gfmAutolinkLiteralFromMarkdown` and
+`gfmAutolinkLiteralToMarkdown`.
+There is no default export.
+
 ### `gfmAutolinkLiteralFromMarkdown`
 
+Extension for [`mdast-util-from-markdown`][mdast-util-from-markdown].
+
 ### `gfmAutolinkLiteralToMarkdown`
 
-Support literal autolinks.
-The exports are extensions, respectively
-for [`mdast-util-from-markdown`][from-markdown] and
-[`mdast-util-to-markdown`][to-markdown].
+Extension for [`mdast-util-to-markdown`][mdast-util-to-markdown].
+
+## Syntax tree
+
+There are no interfaces added to **[mdast][]** by this utility, as it reuses
+the existing [**Link**][dfn-link] interface.
+
+## Types
+
+This package is fully typed with [TypeScript][].
+It does not export additional types.
+
+The `Link` node type is supported in `@types/mdast` by default.
+
+## Compatibility
+
+Projects maintained by the unified collective are compatible with all maintained
+versions of Node.js.
+As of now, that is Node.js 12.20+, 14.14+, and 16.0+.
+Our projects sometimes work with older versions, but this is not guaranteed.
+
+This plugin works with `mdast-util-from-markdown` version 1+ and
+`mdast-util-to-markdown` version 1+.
 
 ## Related
 
-*   [`remarkjs/remark`][remark]
-    — markdown processor powered by plugins
 *   [`remarkjs/remark-gfm`][remark-gfm]
     — remark plugin to support GFM
-*   [`micromark/micromark`][micromark]
-    — the smallest commonmark-compliant markdown parser that exists
+*   [`syntax-tree/mdast-util-gfm`][mdast-util-gfm]
+    — same but all of GFM (autolink literals, footnotes, strikethrough, tables,
+    tasklists)
 *   [`micromark/micromark-extension-gfm-autolink-literal`][extension]
     — micromark extension to parse GFM autolink literals
-*   [`syntax-tree/mdast-util-from-markdown`][from-markdown]
-    — mdast parser using `micromark` to create mdast from markdown
-*   [`syntax-tree/mdast-util-to-markdown`][to-markdown]
-    — mdast serializer to create markdown from mdast
 
 ## Contribute
 
-See [`contributing.md` in `syntax-tree/.github`][contributing] for ways to get
-started.
+See [`contributing.md`][contributing] in [`syntax-tree/.github`][health] for
+ways to get started.
 See [`support.md`][support] for ways to get help.
 
 This project has a [code of conduct][coc].
@@ -164,10 +243,18 @@ abide by its terms.
 
 [npm]: https://docs.npmjs.com/cli/install
 
+[esm]: https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c
+
+[esmsh]: https://esm.sh
+
+[typescript]: https://www.typescriptlang.org
+
 [license]: license
 
 [author]: https://wooorm.com
 
+[health]: https://github.com/syntax-tree/.github
+
 [contributing]: https://github.com/syntax-tree/.github/blob/HEAD/contributing.md
 
 [support]: https://github.com/syntax-tree/.github/blob/HEAD/support.md
@@ -178,14 +265,16 @@ abide by its terms.
 
 [mdast-util-gfm]: https://github.com/syntax-tree/mdast-util-gfm
 
-[remark]: https://github.com/remarkjs/remark
+[mdast-util-from-markdown]: https://github.com/syntax-tree/mdast-util-from-markdown
 
-[remark-gfm]: https://github.com/remarkjs/remark-gfm
+[mdast-util-to-markdown]: https://github.com/syntax-tree/mdast-util-to-markdown
 
-[from-markdown]: https://github.com/syntax-tree/mdast-util-from-markdown
+[mdast-util-to-hast]: https://github.com/syntax-tree/mdast-util-to-hast
 
-[to-markdown]: https://github.com/syntax-tree/mdast-util-to-markdown
-
-[micromark]: https://github.com/micromark/micromark
+[remark-gfm]: https://github.com/remarkjs/remark-gfm
 
 [extension]: https://github.com/micromark/micromark-extension-gfm-autolink-literal
+
+[gfm]: https://github.github.com/gfm/
+
+[dfn-link]: https://github.com/syntax-tree/mdast#link